Use of anti-cyclic citrullinated peptide antibodies and rheumatoid factor in diagnosis of rheumatoid arthritis in a tertiary care hospital.

UNLABELLED: Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease that affects 0.5-1% of the general population and is characterized by a chronic, debilitating, and destructive form of arthritis. Rheumatoid factor (RF) is a frequently used diagnostic test for RA.

OBJECTIVES

To evaluate the significance of anti-CCP and RF antibodies in RA diagnosis, to assess diagnostic utility of anti-CCP antibody for RA in relation to RF, and to assess the combined approach (anti-CCP + RF) for early prognosis of RA.

MATERIALS AND

METHODS

93 patients clinically suspected of RA attending Medicine OPD at ESIC (Employees State Insurance Corporation) Hospital, Bangalore, were included in the study. About 5 ml of blood was collected aseptically from clinically suspected RA patients. Serum was separated and tested for RA factor and anti-CCP antibodies.

STATISTICAL ANALYSIS: Sensitivity, specificity, and positive predictive value were calculated using 2 × 2 table, with fixed row margins (a + b) and column margins (c + d); conventionally, disease is on top and test is on the side.

RESULTS

RA factor is positive in 12 RA patients, anti-CCP patients in 24 RA patients, combined RA and anti-CCP positive in 8 patients, sensitivity of RA factor 33.3%, anti-CCP 66.6%, and RA + Anti CCP 33.3% Specificity of RA factor 17.54%, Anti CCP 1.75%, and RA + Anti CCP 7% positive Predictive value of RA Factor 54.5%, Anti CCP 100%, and RA + Anti CCP 66.6%.

CONCLUSIONS

Anti-CCP antibodies have a high sensitivity and positive predictive value, making them an excellent tool for differentiating RA from other forms of arthritis. Because of its high specificity, RF is a useful screening marker for RA diagnosis.